Re: Add SPLIT PARTITION/MERGE PARTITIONS commands

Hi Dmitry.

On Mon, Sep 1, 2025 at 2:04 PM Dmitry Koval <d(dot)koval(at)postgrespro(dot)ru> wrote:
> Hi!
> Thank you for the notes and patch!

Some additional notes from me.

1) src/backend/parser/parse_utilcmd.c includes are not alphabetically
ordered here
+#include "partitioning/partdesc.h"
+#include "partitioning/partbounds.h"

2) There is unicode dash in the comment of ATExecMergePartitions() here. I
suggest we should stick to ascii.

+ /*
+ * Check ownership of merged partitions — partitions with different
+ * owners cannot be merged. Also, collect the OIDs of these partitions
+ * during the check.
+ */

3) Regarding 17bcf4f545, I see btnamecmp() is collation-aware. Should we
also specify COLLATE "C" every time we do "ORDER BY relname"?

4) This comment sounds misleading. Probably it should say "are contained".

+/*
+ * check_parent_values_in_new_partitions
+ *
+ * (function for BY LIST partitioning)
+ *
+ * Checks that all values of split partition (with Oid partOid) contains
in new
+ * partitions.
+ *

5) Given what latter items say, I think the 1. should say "The DEFAULT
partition must be at most one."

/*
* check_partitions_for_split
*
* Checks new partitions for SPLIT PARTITIONS command:
* 1. DEFAULT partition should be one.

6) Regarding the isolation tests. I see we are exercising INSERTs and
intra-partition UPDATEs. Should we also try some cross-partition UPDATEs?

------
Regards,
Alexander Korotkov
Supabase